Heat-actuated motor



Dec. 30, 1958 J. G. MOORHEAD 2,866,342

HEAT-ACTUATED MOTOR Filed Oct. 9, 1956 a. 34 36 L A14 W/fl INVENTOR.

John G. Moorheud ATTORNE Y5 HEAT-ACTUATED MOTUR John Gerald Moorhead, Siiver Spring, Md, assignor to the United States at America as represented by the Secretary of the Army Application October 9, 1956, Serial No. 614,997

ll Claim. (Cl. 742) (Granted under Tide 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a heat-actuated, spring-operated, device.

An object of this invention is to provide novel means for producing a desired motion.

Another object of this invention is to provide novel means for converting heat energy into mechanical energy.

Still another object is to provide a simple, rugged, economical, one-shot device for producing a mechanical displacement in response to an electrical signal.

Briefly a preferred form of this invention presents a device having a biased spring mounted on an enclosed heat squib by means of a low melting point solder.

The specific nature of the invention as well as other objects, uses and advantages thereof will clearly appear from the following description and from the accompanying drawing, in which:

The figure is a longitudinal sectional view of the novel device of this invention.

In the figure, a heat squib means is designated generally by numeral 10, and may comprise a cylindrical casing 12 having a suitable predetermined thickness, diameter and length. Casing 12 has an integral closed end 14 and an open end 16. Inserted in end 16 is a heat squib 18 which is secured in the casing 12 by a closure 20. Corresponding thread means 22 may be provided to mount closure 20 in end 16 substantially as illustrated. Closure 20 may have extending therethrough in a hermetically sealed relation, a bridge or filament 24. Filament 24 is connected to a suitable source of electrical power and presents a preferred means for energizing the squib 18. The squib 18 may be comprised of a main mixture of nonmetallic powder such as a selenium powder and an oxide such as barium peroxide.

Externally mounted on end 14 of casing 12 is a spring 28. Spring 28 is shown in its biased or loaded state and may present a relatively elongated fiat portion 30. Extending integrally from fiat portion 30 may be side portions 32 and 34. Side portions 32 and 34 may be conveniently flanged, bent or worked in to present end portions 36 and 38, respectively.

End portion 38 is preferably permanently secured to closed end 14 of casing 12. This securement may be effected by a substantially high melting point solder 40. End portion 36 is preferably secured to closed end 14 by a relatively low melting point solder 42 substantially as shown. The melting point of solder 42 should be low enough so that solder 42 will be melted by the heat Patented Eco. 36, 1958 46 should not be affected by this heat energy.

In operation, when current is passed through filament 2t, detonation or ignition of squib 1% will occur. The explosive characteristics of squib 18 upon ignition are negligible to the extent that no failure, fracture, weaken ing, or dislodging of the casing 28 and its associated parts will ensue. Squib 18 will be undergoing substantially a controlled combustion from which heat energy will be generated through the casing 12. This heat energy will be of sufficient quality and quantity to melt solder 42, but not sufiicient to melt solder 46. Because the spring 28 is in a biased condition, end portion 36 will be urged in a direction substantially as indicated by the heavy arrow in the drawing. As will be apparent a substantially circular arc, from 0 to or more, can be traversed by proper spring loading or biasing. The spring thickness and width may be predetermined by taking into account the intended functioning or result contemplated by the predetermined spring movement. Other spring configurations may be employed.

The structure of this invention has considerable advantages in that it is effectively responsive to relatively weak signals. It has superior shock proof characteristics. A desirable delay may be obtained from the movement of squib detonation to the moment that the spring is free to function by conditioning the squib and low melting point solder. Many useful functions and results may be accomplished by the structure of this invention, as for example, moving or displacing rods and pistons, closing or opening valves, and closing or opening electrical contacts. These rods, pistons, valves and contacts could very readily be incorporated into or with the structure of this invention as will be apparent to one skilled in the art. Further by proper fabrication the device of this invention can be reusable countless times or may be disposable after a single use.

It will be apparent that the embodiment shown is only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claim.

I claim:

A device for producing a predetermined mechanical displacement in response to an electrical signal, said device comprising in combination: a cylindrical casing enclosing a heat squib, said casing having a first closed end and a second closed end; an electric filament disposed within said casing and connected to an electric power source, said filament being hermetically mounted by said first closed end; a biased spring having a first inturned end and a second inturned end; said first inturned end being substantially permanently mounted on said second closed end by means of a relatively high melting point solder; said second inturned end being biased and soldered to said second closed end by a relatively low melting point solder; so constructed and arranged that upon energization of said squib by passing a current through said filament, sufiicient heat is generated by said squib to melt said low melting point solder so that said second inturned end is urged away from said casing through an arcuate path, said second inturned end acting as a pivot for said first inturned end.

References Cited in the file of this patent FOREIGN PATENTS 216,539 Great Britain Nov. 26, 1925 

